Field of the Invention
The present invention relates generally to power floats or flotation machines for smoothing and compacting poured concrete prior to finishing. More specifically, the invention relates to a flotation machine having a support structure dedicated to interface with a float pan.
Description of Related Art
Floating is a well-known construction technique used during the process of finishing a newly poured concrete surface. Floating describes the act of passing a flat tool over and downward against a leveled slab of concrete to remove surface imperfections, flatten the surface, and compact the concrete to sink the aggregate and bring water to the surface.
Float tools, or floats, may be designed for manual or power operation. Manual floats are typically used on concrete pours over relatively small areas, such as in residential construction. A manual float typically includes a rectangular surface made of wood, or of metal such as aluminum, magnesium, or steel. Power floats are used for larger pours. A power float is a device powered by an engine or motor that rotates float blades or a float pan. Float blades and float pans are typically made of abrasion-resistant steel. The weight of the power trowel itself provides the downward force necessary to achieve the desired floating effect. One type of power float is a walk-behind power trowel fitted with float blades or combination (float and finishing) blades. Another type of power float is achieved by fitting a ride-on trowel with a float pan accessory that attaches underneath the finishing blades of each trowel, so that the float pans support the trowel and operator above the surface of the concrete while rotating to both smooth the concrete and propel the trowel along its surface.
When using a ride-on trowel as a flotation machine, certain difficulties can arise from retro-fitting a power trowel to function as a power float. The rotor blades of a power trowel are designed primarily for finishing a concrete surface—not for supporting a float pan—and thus the rotor blades provide an imperfect interface. As a result, the float pan can be difficult to center when fitting it to the rotor blades, and if installed off-center, can cause undesirable movement of the trowel or pan during operation. Even when the float pan is properly centered, the ride-on trowel, which can weigh in excess of 2500 lbs, when pressing rotor blades against the float pan can form nonplanar areas on the float pan that cause grooves or furrows in the concrete surface. These must be smoothed over by additional passage of the float pan, or by another power float. Repeated use of a poorly fit float pan can also reduce its the useful life.
What is needed is an advancement in power float design, dedicated to perfecting the floating process itself, that preserves a desired shape of a float plan during power operation.